Ore dressing



Patented Mar. 26, 1940 UNITED STATES 2,194,522 one DRESSING Benjamin B. Harris, Chicago, Ill.

No Drawing. Original application February 13;

- 1935, Serial No. 6,393.

Divided and this application April 24, 1939, Serial No. 269,813

12 Claims.

My invention relates in general to ore dressing.

It relates more in particular to an improved method for producing selective interface modification between the minerals or other constitu ents of an ore and the liquid medium in which they are suspended and their separation.

In a previous application I disclosed the use of certain new types of reagents for flotation purposes. Flotation involves the selective interface modification of one or more types of substances or minerals in an ore. The substances having selectively modified interfacial relations may be separated in various ways, the most widely used method in recent years being the socalled froth flotation method.

While my prior application was not limited to any particular method of securing actual separation, it was directed more particularly to the use of the froth flotation method of separation. For certain purposes, other means of separation of one constituent of an ore from another is preferred. One method which has had some use is the so-called agglomeration or granulation method of which the Cattermole and Murex processes are illustrative.

In froth flotation as ordinarily carried out one constituent of an ore is selectively modified by the reagents added. These reagents may modify the mineral surface by chemical action or adsorption or both or may modify the interfacial relations with the liquid. In most cases it is the function of flotation reagents to so modify interfacial relationships that the mineral particles to be floated are water repellant. Another function of flotation reagents is to produce a froth wherein the selectively modified mineral will be included.

In the method of agglomeration or granulation I have mentioned the selectively modified mineral-liquid interface is wetted with an oleaginous substance to produce or increase water repellency and the water repellant oiled particles separated by mechanical means such as the conventional ore dressing table. The frothing element necessary in froth flotation need no longer be present. I have found however, that it is sometimes advantageous to separate the selectively oiled particles by froth flotation and this may be readily done in most cases 'by the addition of a frother if the particles are not too large. It will be seen from this illustration that the first steps in the agglomeration and flotation processes are identical, namely the production of a selectively modified interfacial relationship between the minerals and the liquid surrounding them.

My present invention relates to reagents for producing interface modification and particularly to selective oiling of mineral particles and The reagents I employ are of a type in which at least one lipophile group of relatively high molecular weight-from six carbon atoms up and a hydrophile group, in the form of an oxygenated acid sulphur containing radical neutralized with a suitable base are present in the same molecule. Preferably a polyhydroxy substance is employed to link the two groups. The type of substance which I use has the lipophile and hydrophile groups in such a state of "balance that very many of my substances will function as anti-spattering agents which will substantially reduce spattering of margarine during frying when employed in margarine made in the conventional manner from milk and oils and fats in small proportions. The character of these reagents will be more fully understood by more specific references thereto.

Some of the most efiicient of my reagents are glycol derivatives in which a high molecular weight fattyacid is esterifled with one hydroxy group of the glycol, and the other hydroxy group of the glycol is esterified with sulphuric acid or some equivalent thereof, the sulphate group being neutralized with a suitable alkaline material such as alkali metal hydroxide including sodium and other metals, ammonia, amines and the like. Of this class I have obtained very good results with lauryl diethylene glycol sulphate (neutralized) and cocoanut fatty acid di-ethylene glycol sulphate (neutralized). Other fatty acids may be employed as a source of lipophile groups in the same type of substance, such as oleic acid, palmitic acid, stearic acid, and other acids derived from fats and oils, either substantially pure or mixtures thereof. For many purposes improved results seem to be obtained if a mixture of fatty acids is employed as a source of lipophile groups, and these acids esterified with at least one hydroxy group of a polyhydroxy substance, leaving at least one free hydroxy group which is afterward esterifledwith a sulphuric acid radical. In this latter step I may employ any of the usual methods of esterification, employing sulphuric acid directly, chlorosulphonic acid under proper conditions, sulphur trioxide, mixtures thereof, or any other reagent or method by means of which a sulphuric acid radical can be introduced at the hydroxy group. 1

In place of carboxylic acid esters of glycol, I may employ the alkyl ethers thereof, and then sulphatethe same to produce products typified generally by the substance dodecyl diethylene glycol ether sulphate (ethanol amine salt), or the sulphated mixed esters of diethylene glycol With the mixture of alcohols obtained by the re duction of mixed cocoanut fatty acids, or other fatty acids derived from ordinary oils and fats known to commerce.

In place of a glycol I may employ glycerol or polymerized products thereof. The methods of producing the reagent are substantially the same as when a glycol is used. Similarly I may use any suitable fatty acids having at least six carbon atoms in their molecular structure. Examples of glycerol derivatives which I may employ with good results are cocoanut oil fatty acid esters (sulphated and neutralized), oleic acid esters of glycerine in which at least one hydroxy group of the glycerine is esterified with sulphuric acid, and the like.

In place of employing fatty acids for esterifying with glycerine or glycols, or the like, I may re-esterify a suitable fat .or oil with a polyhydroxy substance such as glycerine or glycol or polyglycerol by the use of an alkaline or potentially alkaline catalyst, the re-esterification being carried on at a temperature between approximately 200 and 275 degrees C. It will be understood that this is illustrative, as any suitable means of re-esterifying a fat or oil can be used. This reaction mixture consists essentially ofa mixture of fatty acid esters of polyhydroxy substances having free hydroxy groups and at least one free hydroxy group is then esterified with a sulphuric acid radical to produce a final product which when neutralized is suitable for use according to my invention.

The'poly'glycerols which I may employ are produced by polymerizing glycerine employing a relatively small amount, from about one-tenth percent to one percent of an alkaline catalyst, such as sodium hydroxide, and heating the mixture preferably in a non-oxidizing atmosphere until a molecular weight determinationjndicates that the desired amount of polymerization has taken place. A product having the average molecular weight of a diglycerol or triglycerol is in general suitable for the purpose of myinvention. This polyglycerol product is then treated to produce fatty acid esters thereof with at least one free hydroxy group, and the resulting product is thereafter treated to produce the sulphate according to any suitable or conventional method. I may also employ other types of polyhydroxy substances such as sugars, sugar alcohols, mannitol, sorbitol and the like, or, in fact, any polyhydroxy substance capable of being esterified with fatty acids to produce esters with free hydroxy groups which may afterward be sulphated to produce the final product. I may also employ alkyl sulphates or sulphonates of relatively high molecular weight in my present invention, although for some purposes they do not give as suitable and satisfactory results as the substances previously described, wherein a polyhydroxy substance is employedto link the lipophile group and the hydrophile sulphate group.

In the sulphating step, as previously noted,

any conventional or suitable procedure may be i used. Generally it is not admissible to subject the product to too rigorous a treatment, and in some cases unesterified hydroxy groups will usually be present. In fact, some portion of substances may be entirely free of sulphate groups. The product may be used, nevertheless, as the presence of a. proportion of unsulphated product may be used; in fact, at times, somewhat better results are obtained.

These reagents selectively modify the interface relationships of certain minerals so they may be oiled and separated by either froth flotation or agglomeration and tabling. In some cases the oiling is not necessary-the reagents themselves being suflicient,-some examples of this type are discussed later. The oiling when done may be done simultaneously with the selectivev interfacial modification produced by my reagents or may be carried on subsequently in a separate step.

The oiling may advantageously be effected by means of an aqueous emulsion containing the oil and the reagent and highly selective separations may be accomplished by varying the interface modifying reagent and the oil.

Among the interface modifying reagents which may be used for the purposes of my invention are, for example, lauryl diethylene glycol sulphate (ammonium salt), normal decyl sodium sulphate, sodium dodecyl sulphate, butyl carbitol sulphate (sodium salt), oleyl diethylene glycol sulphate (ammonium salt), stearyl diethylene glycol (ammonium salt), sodium' salt of mono-n caprylil diethylene glycol sulphate, monoethanolamine salt of butyl carbitol sulphate, lauryl sulphonic acid (sodium salt), normal octyl sodium sulphate, heptyl sodium sulphate, olein disulphate, sulphated oleic acid ester of diglycerol, sulphated mono-fatty acid. esters of glycerol such as the sulphated stearic acid esters of glycerol. It, will be appreciated that the'variousv reagents will have different efficacies and the amounts thereof employed may vary.

The oleaginous materials are likewise open to variation, among such materials being, for example, corn oil, cottonseed oil, olive oil, palm oil, petroleum oils such as crude oils; sardine oil, menhaden oil, lard oil, and the like.

As an example we may consider an ore of rutile and apatite. Ti02 asrutile. It was ground through 20 mesh and conditioned in a thick pulp with an emulsion of water, corn oil and the sulphated diethylene glycol derivative of the mixed cocoanut oil fatty acids. Using in all .4 lb. per ton of the sulphated reagent and 3 lbs. per ton corn oil, the ore was conditioned by thorough mixing. Water was then added to produce a pulp suitable for tabling. -The result of tabling is shown in the following table:

This ore contained 3.6%

, In general, however, it is preferable to add the r I Lake Superior district contained 30.2% Fe, the

gangue being silica. The ore was ground to pass 14 mesh and mixed with a little water, 2 lb. per ton H2804 and 1 lb. per ton sulfated diethylene glycol ester of mixed cocoanut oil fatty acids.

This process may be used on chromite, magnetite, apatite, limestone, dolomite, magnesite and bauxite, without especial care in the selection of reagent or oil. In other cases, however, the selection of interface modifying agent is very critical. Such a case is the separation of sylvite and halite as they occur at Carlsbad, New Mexica. Since these minerals are soluble, the surface modifying agent must be stable to saturated brine. That is the reagent must be soluble enough to promote oiling but must selectively effect the interfacial relations between either sodium' or potassium chloride and brine. Since potassium salts are in general more insoluble than sodium salts, I have hypothecated that the reagent acts in this case by. precipitation of a film of potassium salt; but that enough must remain in solution to serve as an oil carrier.

The reagent which has produced unusually good results for the separation of these two minerals is mixed cocoanut fatty acid diethylene glycol sulphate neutralized with ammonia, sodium hydroxide, ethanol amine, or triethanolamine. Still other neutralizing substances may be used but in general very satisfactory results have been obtained if the product is neutralized by the substances described. My process may be carried out according to several procedures to produce a mixture of brine, mineral oil and the fatty acid diethylene glycol, sulphate, neutralized with triethanolamine, or ammonia, wherein the oil is selectively adsorbed by'the sylvite but does not coat the halite, with the result thatthe sylvite is formed into glomerules of such composition and size that ordinary tabling is sufiicient to separate them. The concentrate consists of 85 to 95% potassium chloride, the tailings containing only about 5% of potassium chloride, or less. The concentrate may be air dried and treated to produce a product acceptable for agricultural purposes. The presence of small amounts of oil is not objectionable.

According to one procedure-I form an emulsion of 25 pounds of oil, one pound of the reagent, and enough brine made from the ore to produce a total of 100 pounds of emulsion. This emulsion is then added to thev ore, which is in the form of a relatively thin pulp of 12 to 16 mesh ore, the proportions being such that about one and one-half to four pounds of reagent and 10 to 15 pounds of oil are present in about a ton of ore. The ore with the emulsion added thereto is agitated slowly by means of a slow-moving stirring-arm, or in any other suitable manner, for approximately five minutes, until the sylvite is agglomerated into particles of a suflicien't character and size to permit easy separation. The glomerules are easily observed by the operator for the purpose of determining when the product has advanced to a suitable condition in and dispersed uniformly.

for treatment on a separating table. Although tabling is very satisfactory for the purpose, any other suitable method of separation commonly used in the ore dressing industries can be employed.

Another method is to add the oil to a very thick pulp and introduce the reagent dispersed in an additional amount of water. By this method the amount of reagent may be reduced to 1.6 lbs. per ton of ore. The results of atest made in this way are shown in .the following table.

Weight Percent Total K01 'liroduct percent K01 percent Table concentrates 45.2 85.1 95.2 Table toils 54. 8 4. I 4. 8 Composite 100 40. 6 100 According to another modification, 2,000 lbs. of sylvinite reduced to a size of 12 to 16 mesh, are moistened with a brine (a saturated brine prepared from the ore is convenient). To this are added 4 lbs. of ethanolamine salt of mixed cocoanut fatty acids esters of. diethylene glycol sulphate, with thorough stirring to produce a substantially uniform mixture. This mixture can be seen to have incorporated considerable air. Fifteen pounds of crude oil are now stirred Approximately 2,000 lbs. of brine are incorporated, and the total of approximately two tons tabled. A high grade concentrate of sylvite, averaging about 90% KCl, is obtained, with only about 5% KCl in the tails. The tails may be in part recirculated to increase the proportionate yield of potassium. The concentrate may be dried suitably, in air, for example. and may be crushed if desired to givean acceptable agricultural potassium chloride product.

The amount of reagent and oil used'are not extremely critical insofar as separation is concerned, but in the interest of economy no more reagent should be used than is sumcient to produce a good separation. No more than enough oil to wet the sylvite particles should be employed because it has a tendency to separate out on the tables or other equipment used for separation, and this requires periodic cleaning which can be avoided if the amount of oil is cut down.

While many oil constituents may be employed, the best results are obtained if a crude oil is used. I have found that Gulf Coast crude oils produce particularly good results. I have also found that if the crude oil is treated to remove some of the volatile constituents, the amount of oil can be decreased and in general somewhat better results are obtained.

Other reagents may be successfully used in the agglomeration of sylvite such as oleyl diethylene glycol sulphate (sodium salt), mixed cocoanut fatty acid glycerol sulphate (ammonium salt), sodium salt of sulphated cocoanut fatty acids, lauryl sulphonic acid, octyl sulphonic acid, decyl sulphonic acid.

I have also found that the mineral langbeinite containing potassium sulphate may be treated in accordance with my invention, and other salts such as those of barium, lead, zirconium and ferric iron may be separated from salts of potas-- sium, zinc, calcium or magnesium.

It will be obvious that examples of the application of my invention to the separation of soluble salts might be multiplied indefinitely but the foregoing will make my invention clear and I wish to be limited only by the appended claims.

Wherever the term higher is employed herein and in the claims it will be understood to mean from six to fourteen carbon atoms unless otherwise specifically stated. i

This application is a division of my copending application Serial No. 6,393, filed February 13, 1935. I

What I claim as new and desire to protect by Letters Patent of the United States is:

1. The method of concentrating non-sulfide minerals which comprises forming an emulsion of an ore containing the mineral with an aqueous material, an oleaginous material and a sulphate of a straight chain aliphatic alcohol containing at least eight carbon atoms, whereby to cause the oleaginous material to oil said mineral and form relatively large aggregates, and agitating said emulsion on a separating table to separate said relatively large aggregates.

2. The method of concentrating non-sulfide minerals which comprises forming an emulsion of an ore containing the mineral with an aqueous material, an oleaginous material, a fatty acid ester of a water-soluble .polyhydroxy substance wherein ahydroxy group of the polyhydroxy substance is esterified with a sulphate radical, whereby to cause said mineral to form relatively large aggregates admixed with oleaginous material, and then treating the emulsion to remove said relatively large aggregates.

3. The method of concentrating non-sulfide minerals which comprises forming an emulsion of an ore containing the mineral with an aqueous material, an oleaginous material, a fatty acid ester of a polyhydric alcohol wherein a hydroxy group of the polyhydric alcohol is esterified with a sulphate radical, whereby to cause said mineral to form relatively largeaggregates admixed with oleaginous material, and then treating the emulsion to remove said relatively large aggregates.

4. The method of concentrating non-sulfide minerals which comprises forming an emulsion of an ore containing the mineral with an aqueous material, an oleaginous material, a fatty acid ester of a glycol wherein a hydroxy group of the glycol is esterified with a sulphate radical, whereby to cause said mineral to form relatively large.

aggregates admixed with oleaginous material, and then treating the emulsion to remove said relatively large aggregates.

5. The method of concentrating non-sulfide minerals which comprises forming an emulsion of an ore containing the mineral with an aqueous material, an oleaginousmaterial, a fatty acid ester of a water-soluble polyhydroxy substance wherein a hydroxy group of the polyhydroxv substance is esterified with a sulphate radical, whereby to cause said mineral to form relatively large aggregates admixed with oleaginous material, and then tabling the emulsion to remove the relatively large aggregates.

6. The method of concentrating non-sulfide minerals which comprises forming an emulsion of an ore containing the mineral with an aqueous m terial, an oleaginous material, a fatty acid ester of a polyhydric alcohol wherein a hydroxy group of the polyhydric alcohol is esterified with a sulphate radical, whereby to cause said mineral to form relatively large aggregates admixed with oleaginous material, and then tabling the emulsion to remove the relatively large aggregates.

7. The method of concentrating non-sulfide minerals which comprises forming an emulsion of an ore containing the mineral with an aqueous material, an oleaginous material, a fatty acid ester of a glycol wherein a hydroxy group of the glycol is esterified with a sulphate radical, whereby to cause said mineral to form relatively large aggregates admixed with oleaginous material, and then tabling the emulsion to remove the relatively large aggregates.

8. The method of separating sylvite from halite which comprises forming an emulsion of brine containing solid particles of said minerals, an oleaginous material and a chemical having a relatively high molecular weight lipophile group and a hydrophile sulphur containing group, whereby to form relatively large aggregates of sylvite admixed with the oleaginous material, and then treating the emulsion to remove said relatively large aggregates.

9. The method of separating sylvite from halite which comprises forming an emulsion ofbrine containing solid particles of said minerals, an oleaginous material and a fatty acid ester of a glycol in which one hydroxy group of the glycol is esterified with a neutralized sulphate group,

whereby to form relatively large aggregates of sylvite admixed with the oleaginous material, and then treating the emulsion to remove said relatively large aggregates.

10. The method of separating sylvite from halite which comprises forming an emulsion of brine containing solid particles of said minerals, an oleaginous material and la'uryl diethylene glycol sulphate (neutralized), whereby to form relatively large aggregates of, sylvite admixed with the oleaginous material, and then treating the emulsion to remove said relatively large aggregates. 1

11. The method of separating sylvite from halite which comprises forming an emulsion of brine containing solid particles of said minerals, a crude mineral oil, lauryl diethylene glycol sulphate (neutralized) and a chemical having a relatively high molecular weight lipophile group and 'a hydrophile sulphur containing group, whereby to form relatively large aggregates of sylvite admixed with the oleaginous material, and then treating the emulsion to remove said relatively large aggregates.

12. The method of concentrating non-sulfide minerals which comprises mixing with an ore aqueous material, oleaginous materialand a sulphate of a straight chain aliphatic alcohol containing at least eight carbon atoms, whereby a reagent is selectively adsorbed with the surface of one constituent of the ore, and then tabling the resultant mixture to remove a portion of the ore.

BENJAMIN R. HARRIS. 

